1. Field of the Invention
The present general inventive concept relates to an image forming device to perform an auto color registration and a method thereof. More particularly, the present general inventive concept relates to an image forming device to perform an auto color registration according to different conditions of different print modes.
2. Description of the Related Art
With the development of electronic technology, peripheral devices such as a printer, a scanner, and so forth, in addition to a computer, have been actively spread. Particularly, as manufacturers strive to be first in developing printers, laser printers, which have remarkable effects in printing quality, printing speed, noise occurrence, and so forth, in comparison to the existing dot printers and inkjet printers, have been increasingly used. A laser printer performs a printing operation in a manner that it gets toner on an organic photoconductive unit (OPC), transfers the toner put on the OPC to a printing paper, and fuses the toner on the printing paper with high heat and pressure.
The laser printer prints an image through processes of charging, writing, developing, transferring, fusing, and so forth. The charging is a process of forming negative charge on the OPC surface through Corona discharge by applying a high voltage (of about 7000V) to a discharger. The writing is a process of forming a latent image by extinguishing the negative charge formed on the OPC surface in the form of a letter through scanning of laser beams on the OPC surface. The developing is a process of making toner particles having the negative charge stick to the latent image portion of the OPC surface. The transferring is a process of pulling the negatively charged toner particles formed on the OPC surface in a direction of a printing paper by forming a negative charge on a rear surface of the paper through the applying of a specified transfer voltage to a transfer machine when the paper passes between the OPC and the transfer machine. The fusing is a process of completely fusing the toner particles on the paper by applying proper heat and pressure to the toner formed on the paper.
Recently, uses of color laser printers have been widespread. The color laser printer generally represents a color image by using toners of four colors, CMYK. In order to print a clear image, the color laser printer generally performs the printing work for each of the color toners by using four OPCs. Also, in order to locate the respective color toners at correct positions, the transferring process is performed in two stages by using an intermediate transfer belt (ITB).
On the other hand, in order to express the colors, the toners should be accurately superimposed and transferred onto the same position by using a plurality of OPCs and transfer machines. However, as the number of prints is increased, the toner transfer positions may be mismatched due to operation errors among the transfer machines. That is, the respective transfer machines cannot transfer the toner in the same position, and this causes the edge portion of the image to be blurred.
Conventionally, in order to solve the above-described problems, an auto color registration function has been introduced. This auto color registration function is performed at predetermined intervals. Typically, the auto color registration is to match the transfer positions in a manner that if transferred images of the respective transfer machines are mismatched by X dots when N printing papers are printed, the transfer positions are adjusted by X dots whenever N printing papers are printed.
However, whenever the color registration work is performed, a large amount of toner is consumed, and thus the amount of waste toner is increased. Even if a user sets the present mode to a toner save mode for saving toner, the color registration work is performed with a large amount of toner consumed, and this is against the user's intention to save the toner.
In addition, since the user cannot use the image forming device while the color registration is performed, the frequent color registration works may cause the user inconvenience. Recently, as image forming devices have been increasingly used at home, personal users are taking serious considerations of saving of toner and increasing convenience in use. However, the conventional image forming device having the auto color registration function does not meet the users' demands.